building custom ISP shield, what pin for LEDs?

Other Hardware General Electronics
1

I looked at the code for Arduino ISP and it seems there are 2 possible pin sets:

#ifndef ARDUINO_HOODLOADER2

#define RESET     10 // Use pin 10 to reset the target rather than SS
#define LED_HB    9
#define LED_ERR   8
#define LED_PMODE 7

and

#define RESET     	4
#define LED_HB    	7
#define LED_ERR   	6
#define LED_PMODE 	5

Is the first set correct for standard UNO? I don't remember ISP code being this large or complicated but the last time I looked at it was before version 1.0 so I'd imagine a lot has changed since then. I am having a bit of trouble understanding the purpose of current style and old style, was there an Arduino board that has UNO form factor but used different pinouts?

2

The ArduinoISP sketch is set up to use the top pin out (10, 9, 8, 7). That is what I used to build my programmer shield for an Uno.

3

The reason for the second set of pins is described in the comment:

// HOODLOADER2 means running sketches on the atmega16u2 
// serial converter chips on Uno or Mega boards.
// We must use pins that are broken out:
#else 

#define RESET     	4
#define LED_HB    	7
#define LED_ERR   	6
#define LED_PMODE 	5

Since the code could also run on an atmega16u2 with less usable pins.

Incidentally, I have also recently joined the ranks of those who have created a custom programmer. You might find something of use to you here: Multiprog v1.0 - Combined HighVoltage + ISP + USBTTL adapter/programmer - Exhibition / Gallery - Arduino Forum

4

Thanks for the info. I don't have 16u2 based Arduino for programming, just for USB to serial on Arduino boards. The first set of numbers will be used to finalize my design.

6v6gt:
Incidentally, I have also recently joined the ranks of those who have created a custom programmer. You might find something of use to you here: Multiprog v1.0 - Combined HighVoltage + ISP + USBTTL adapter/programmer - Exhibition / Gallery - Arduino Forum

I'll keep this in mind if I ever needed high voltage programming. Right now I have ATTiny 44/84 and ATTiny 45/85 shield (no LEDs as they are tiny board) and am currently doing 324/644/1284 which is a huge chip requiring bigger PCB so I ended up with extra space that I could slip in a few LEDs for status. Is this the biggest DIP chip of all AVR chip? ATMega2560 does not come in DIP AFAIK.